4.1 Capacity vs. constraints
Although the project examines both "capacity and constraints," in many cases, constraints are simply the reverse of capacity: the environmental, infrastructure, and financial limits that can influence the scale of settlements and their ability to accommodate growth. Table 1 indicates some ways of defining and determining capacity and constraints in water and wastewater services.
Table 1: Types of capacity and constraints data
Types of capacity data | Types of constraints data |
- Designed capacity of a water or wastewater plant
- Scale and extent of major water and sewer pipes
- Number of connections, and/or population served
- Average and maximum flows through a plant
- Reserve capacity
- Plant classification
- Aquifer capacity and water takings from aquifers
- Surface water body capacity
- Assimilative capacity of water bodies receiving effluent
| - Groundwater limits
- Surface water limits
- Type of water bodies receiving effluent
- Assimilative limits of water bodies receiving effluent
- Limits on subsurface sewage disposal
- Inflow and infiltration data
- Plant and system costs - capital, operations, lifecycle
- Drought data; climate change data
- Age of water and wastewater system elements
- Evidence of failure in water and wastewater systems
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